Advances in technology have resulted in smaller and more powerful computing devices. For example, there currently exist a variety of portable personal computing devices, including wireless computing devices, such as portable wireless telephones, personal digital assistants (PDAs), and paging devices that are small, lightweight, and easily carried by users. More specifically, portable wireless telephones, such as cellular telephones and Internet Protocol (IP) telephones, can communicate voice and data packets over wireless networks. Many such wireless telephones incorporate additional devices to provide enhanced functionality for end users. For example, a wireless telephone can also include a digital still camera, a digital video camera, a digital recorder, and an audio file player. Also, such wireless telephones can execute software applications, such as a web browser application that can be used to access the Internet. As such, these wireless telephones can include significant computing capabilities.
A mobile communication device, such as a wireless phone, may include wireless networking (e.g., Wi-Fi) capability. For example, the device may search for available wireless networks and may connect to a particular wireless network that is available. Wireless networks may be secured or unsecured. When the wireless network is secured, the device may also “remember” authentication details associated with the wireless network (e.g., a network password) so that subsequent connections to the wireless network may be setup faster. Sometimes, a mobile device may transition in and out of a particular wireless network coverage area within a short amount of time. For example, a train passenger having a Wi-Fi enabled device may enter and leave a particular railway station's Wi-Fi coverage area within a matter of minutes, if not seconds. Typical authentication methods may not be fast enough (e.g., may involve too many message exchanges) to enable the device to setup an authenticated Wi-Fi session and send/receive data in such a short period of time.
Wireless networks can implement security using various authentication protocols. One example of an authentication protocol is extensible authentication protocol (EAP). When used for wireless network authentication, EAP may involve exchange of multiple messages between a mobile device, an access point, and an authentication server. To make subsequent re-authentications faster, request for comments (RFC) 5296 defines EAP re-authentication protocol (ERP), which may enable faster re-authentications under certain conditions after a full EAP authentication has been performed. During an ERP re-authentication, various keys may be generated and used. The keys may be associated with validity time periods (e.g., lifetimes), and may expire when the validity time periods have elapsed. Because the mobile device may be unaware of the key lifetimes, the mobile device may attempt to initiate an ERP re-authentication even though the keys have expired. Upon determining that the ERP re-authentication was unsuccessful, the mobile device may initiate a full EAP authentication and generate new keys. However, the additional messaging round trip(s) involved in the unsuccessful ERP re-authentication may increase an overall link setup time of the mobile device.